Bad news first -- the PlayStation Network will be (partially) taken offline starting on April 14, beginning at 8am PST. It will return at 11pm PST, and the only thing that will be affected will be access to the PlayStation Store. So if you were planning on buying flOw tomorrow after holding off for all of these months, you're out of luck.
The good news is that during this time, Sony will be upgrading the PlayStation Store! This upgrade takes the store out of the web-based environment, and adds a slew of new features and fancy upgrades. Don't believe me? Check the video above.
It should be noted that this down time will not affect other PlayStation Network services, so feel free to play Resistance, Warhawk, Unreal Tournament III, or whatever it is you crazy kids do. So unless you planned to spend money tomorrow, carry on as you do.